Abstract: This paper introduces the concept of time-frequency channels into multi-radio multi-channel 802.11 wireless mesh networks for the first time. Time-frequency channels are gotten by dividing wireless resource from two dimensions: time and frequency. This division scheme increases the number of channels, makes channel division much fine, and does preparation for improvement of the channel utilization rate. The quasi-dynamic channel allocation algorithm is proposed based on the time-frequency channel. This algorithm shall be combined with other fix channel allocation algorithms to realize quasi-dynamic channel allocation and achieve maximum throughput with the load changes on each link. Firstly, this algorithm distributes same number of time-frequency channels to each link and the left time-frequency channels are taken as common channels. During the communication process, every link shall make use of its own channels and idle common channels. If the channels assigned to a link are not enough and some channels of other links are idle, this link can occupy these idle channels temporarily. Theory analyses and simulation results prove that the algorithm can improve the throughput of the system effectively.